JPH05225290A - Shape correction system by three dimensional parametric function - Google Patents

Abstract

PURPOSE:To easily correct the shape of a three dimensional model by the parametric function. CONSTITUTION:This system has a three dimensional parametric specification model storage part 1 which uses the parametric function so as to correct the shape of the three dimensional model, a shapecorrected model table extraction part 2 which extracts three dimensional data whose shape is to be corrected from a drawing data base to a table, a three dimensional model consistency inspection part 3 which inspects the consistency of the three dimensional model after the shape correction, and a shape correction model drawing DB storage part 4 which stores the three dimensional model in the drawing data base when the consistency of the three dimensional model is guaranteed in the table.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a computer-aided three-dimensional machine design support system (CAD) and to a method for modifying the shape of a three-dimensional model.

[0002]

2. Description of the Related Art Conventionally, shape correction by a parametric function in a two-dimensional model has been realized, but it has not been realized in a three-dimensional model, and elements must be deleted once and recreated. When trying to realize the shape correction by the parametric function in the three-dimensional model, the data structure itself is complicated and there are too many inspection items for the consistency of the three-dimensional model, which makes the processing difficult and the system complicated. Is.

[0003]

As described above, when the shape of a three-dimensional model is conventionally modified, unlike the two-dimensional model, the solid model is the target of the three-dimensional model.
Since the geometric data includes a plane and a two-dimensional curved surface, it is difficult to check the consistency of the three-dimensional model after the shape correction.

[0004]

According to the method of the present invention, in a method of correcting the shape of a solid model of a computer-based three-dimensional mechanical design support system, means for using a parametric function to correct the shape of the three-dimensional model, and a shape Means for extracting the corrected three-dimensional data from the drawing database into a table, and means for inspecting the consistency of the three-dimensional model after the virtual shape correction in the table,
Means for storing the three-dimensional model in the drawing database when the consistency as the three-dimensional model is guaranteed in the table.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, the present invention will be described with reference to the drawings.

FIG. 1 shows the flow of shape correction processing by the three-dimensional parametric function according to the present invention. The processing is roughly divided into four stages. That is, a three-dimensional parametric designated model storage unit 1 that stores a parameterized model instructed by a parametric function, a shape correction model table extraction unit 2 that extracts three-dimensional data whose shape is to be corrected from a drawing database into a table, The 3D model consistency checker 3 that virtually checks the consistency of the 3D model after the shape correction in the table, and the 3D model consistency check unit 3 when the consistency as the 3D model is guaranteed in the table. Store dimensional model in drawing database,
It is the shape correction model drawing DB storage unit 4.

FIG. 2 is a file-related diagram of the present invention.
This figure is a diagram expressing the flow of processing from the angle of the file structure, and clarifies the mutual relationship between the file structure and the functions.

Next, one embodiment of the present invention will be described in detail with reference to FIG. FIG. 3 is a diagram for explaining an example of the three-dimensional parametric function according to the present invention. The components of the solid model of FIG. 3 are 8 faces, 18 lines, and 12 points.

The dimension values a and b of the dimension line added to the three-dimensional model of FIG. 3 are parameterized, and the shape correction of the three-dimensional model is realized by freely changing these values. A description will be given according to the flow of FIG. In addition, a is the distance to the surface 2 with the surface 1 as the reference surface, and b is the surface 1
Represents the distance to the surface 3 with reference to.

(1) First, the three-dimensional parametric designation model storage unit 1 stores element data (points, lines,
The surface) and the parameterized dimension value data to be added to it are stored.

In the case of FIG. 3, if the dimension value data of a indicates the distance to the surface 2 with respect to the surface 1 and has the information of the length 20 before the correction, and if parametric designation is made a ← 40, Information is also set. Similarly, the dimension value data of b indicates the distance to the surface 3 with reference to the surface 1, and stores the original length 80 and the information of b ← 70 of parametric designation.

There are various other patterns in the dimension value data, such as line-to-line distance, point-to-point distance, sphere or circle diameter, and radius.

(2) Shape correction model table extraction unit 2
Searches for elements whose shape is to be corrected from the geometric data specified by the parametric function, and extracts the geometric data to be shape-corrected from the drawing database into a formatted table (shown in table specifications in FIG. 5). To do.

The process of extracting the geometric data whose shape is to be corrected into the table when moving the surface 2 will be described in detail with reference to FIG. As shown in FIG. 4B, the points forming the moving surface 2 are T1, T2, T3, and T4. The lines forming surface 2 are S1, S2, S3, S4. These constituent points and constituent lines are unconditionally set in the table. Also, set the surface 2.

Next, FIG. 4 (3) shows that the related element groups of the four points constituting the surface 2 are analyzed and set in the table. There are three line segments connected to T1, and all these are set in the table, but S
Since S1 and S4 have already been set in the table, S5 is set here. Similarly, T2, T3, T4
Check the line segment connected to
7. Set S8 on the table. In addition, S5-S8
Are lines other than the lines S1 to S4 forming the surface 2.

The above is the process of extracting points and lines into the table when the surface 2 is moved, but the surface exists when the shape of the three-dimensional solid model is modified. Therefore, it is necessary to set all the surfaces on the left and right of the line segment extracted in the table of S1 to S8 in the table. The geometric data extracted to the table when the surface 2 is finally moved is shown in FIG.
Thus, the number of face elements is 5, the number of line elements is 8, and the number of points is 4.

(3) The three-dimensional model conformity checking unit 3 virtually corrects the geometric data to be shape-corrected in the table and checks whether the shape of the three-dimensional model is destroyed. FIG. 5 shows the table specifications, but what is important here is the conversion matrix in the point table. As shown in FIG. 3, the transfer matrix is entered when a becomes 20 → 40 and b becomes 80 → 70. Then, from this conversion matrix, geometric information of points, lines, and surfaces is corrected in the table, and the consistency of the three-dimensional model is checked in the table. In the case of the example in FIG. 3, the parameterized dimension value data a and b are a before the shape correction.
When <b but corrected a> b, the direction of the normal vector of surface 2 is reversed in the table.

In this case, the three-dimensional model conformity checking unit checks that the shape cannot be corrected because the conformity as a model is broken. In addition, it is checked whether the constituent points of the plane are on the same plane, the length of the line becomes 0, or the direction of the line is reversed.

(4) Finally, the shape-corrected model drawing DB storage unit 4 updates the shape-corrected three-dimensional model to the drawing DB when the consistency of the three-dimensional model is guaranteed in the table. As shown in FIG. 3B, the shape-corrected three-dimensional model of a = 40 and b = 70 is stored in the drawing DB.

[0020]

As described above, the present invention improves the operability by correcting the shape of the three-dimensional model using the parametric function, and in the conventional three-dimensional machine design support system (CAD) using a computer. There is an effect that the three-dimensional parametric function, which cannot be realized because the processing is difficult, can be easily processed by an efficient means.

[Brief description of drawings]

FIG. 1 is a diagram showing a flow of processing of shape correction by a three-dimensional parametric function of the present invention.

FIG. 2 is a file relation diagram in the present invention.

FIG. 3 is a diagram for explaining a specific example of the present invention.

FIG. 4 is a diagram for explaining a processing example of the present invention by the example shown in FIG.

FIG. 5 is a diagram showing an enable specification used in the present invention.

[Explanation of symbols]

 1 3D parametric designated model storage unit 2 Shape correction model table extraction unit 3 3D model consistency inspection unit 4 Shape correction model drawing DB storage unit

Claims (1)

[Claims] 1. A method for correcting the shape of a solid model of a computer-based three-dimensional mechanical design support system, means for using a parametric function to correct the shape of a three-dimensional model, and three-dimensional data to be shape-corrected from a drawing database. Means for extracting into the table, means for virtually checking the consistency of the three-dimensional model after shape correction in the table, and three when the consistency as the three-dimensional model is guaranteed in the table. And a means for storing a dimensional model in a drawing database.